The solution works well! Thank you 
However, I am getting this error if the text selection backward is under 300.
This happens when I point my cursor on a short text and it doesn’t reach 300 characters backward.
I would also like to still make it work even in situations like this.
Are you able to fix it, please?
Lastly, how do I get the values of the selected text so I can process it on another workflow?
Right now I am still using a seperate “text selector” plugin to get the values of the selected text and so that I can process it on the next workflow.
Maybe can you also add here the value of selected text?